Video imaging device, video conversion device, and video edition device

ABSTRACT

When an image signal, which was picked up in a 24p image format and temporarily recorded on a temporary recording device, is read in a 60i image format, the image signal is subjected to a 2:3:2:3 pull-down conversion process so that it becomes possible to omit compressing/expanding processes. At this time, the reading operation is controlled on the basis of the figure of time codes so that the pull-down conversion system at the time of a joining image-pickup process is maintained. In this case, by properly switching controlling methods among a plurality of pull-down controlling methods, it is possible to achieve an image conversion system capable of providing an optimal image conversion process in accordance with desired image-pickup purposes and editing processes.

FIELD OF THE INVENTION

The present invention relates to an imaging system (e.g. video camera)which picks up an image in an image format of 24 frames/second, andoutputs the image signal in an NTSC system (480/60i), a camera recorderwhich further has a recording function, an image conversion system whichconverts an image signal that has been picked up in the image format of24 frames/second to an image signal in the NTSC system, or a devicewhich extracts an image signal of 24 frames/second as picked up, fromthe signal recorded by the arrangement of the present invention, andagain edits the signal.

BACKGROUND OF THE INVENTION

Conventionally, when an image signal, picked up in a progressive imageformat of 24 frames/second (hereinafter, this image signal is referredto as a 24p image signal), is recorded as an image signal in aninterlace image format of 60 fields/second (hereinafter, this imagesignal is referred to as a 60i image signal), a conversion processreferred to as a 2:3:2:3 pull-down system is generally carried out.

FIG. 14 schematically shows the process of the 2:3:2:3 pull-down system.In FIG. 14, frame data corresponding to consecutive 4 frames of 24pimage signals are indicated as A, B, C and D. FIG. 14 shows the processin which the 60i image signal corresponding to these 4 frames isconverted with the time axis thereof being adjusted. In these processes,frame data A of a 24p image signal are separated into field data (Ao)consisting of odd lines of the 60i image signals and field data (Ae)consisting of even lines thereof. These field data (Ao) and (Ae) arerespectively recorded on areas of field numbers 1 and 2 of the 60i imagesignal. Successively, in the same manner, frame data b of the 24p imagesignal are recorded on areas of field numbers 3, 4 and 5 of the 60iimage signal. Frame data C of the 24p image signal are recorded on areasof field numbers 6 and 7 of the 60i image signal. Frame data d of the24p image signal are recorded on areas of field numbers 8, 9 and 10 ofthe 60i image signal. Thereafter, the above-mentioned processes(processes in which frame data corresponding to 4 frames of the 24pimage signal are converted to field data, and then recorded on 10 fieldsof the 60i image signal in a partially overlapped state of 2:3:2:3) arecarried out in a cycle of 4 frames of the 24p image signal. Thisconversion process corresponds to the 2:3:2:3 pull-down conversionprocess.

In recent years, techniques in which images are compressed on a framebasis and recorded have been widely used. In the above-mentioned 2:3:2:3pull-down conversion process, when a compression process is furthercarried out, the process is carried out in the following manner. Here,the compression process is explained by exemplifying a case in whichframe data A of frame number 1 of a 60i image signal shown in FIG. 14are compressed. In this case, field data (Ao) and (Ae) of the 60i imagesignal that have been subjected to the 2:3:2:3 pull-down conversionprocess are once combined into frame data A, and then subjected to acompression process. Hereinafter, the 60i image signal which has beensubjected to the 2:3:2:3 pull-down conversion process and compressed inthis manner is referred to as the compressed 60i image signal (2:3).

Upon reproducing and editing, frame data as picked up (frame data of a24p image signal) are extracted from the compressed 60i image signal(2:3). More specifically, the compressed 60i image signal (2:3) isinversely converted to a 24p image signal in a compressed state(hereinafter, referred to as the compressed 24p image signal). In thiscase, the frame data of the 24p image signal in its compressed state areextracted in order to reduce the amount of data and to preventdegradation in the image.

In this inverse conversion process, frame data A, B and D of thecompressed 24p image signal are inversely converted from the field datastored in areas of frame numbers, 1, 2 and 5 of the compressed 60i imagesignal (2:3). Frame data C of the compressed 24p image signal areinversely converted from the field data stored in areas of frame numbers3 and 4 of the compressed 60i image signal (2:3).

In this inverse conversion process, for example, field data (Ao) andfield data (Ae) corresponding to frame A (frame number 1) of thecompressed 60i image signal are first combined to frame data A, and thencompressed. With this arrangement, the field data (Ao) and (Ae),extracted from the frame number 1 of the compressed 60i image signal(2:3) form frame data A of the compressed 24p image signal. In the samemanner, the field data (Bo, Be) and (Do, De), extracted from the framenumbers 2 and 5 of the compressed 60i image signal (2:3) form frame datab, D of the compressed 24p image signal.

However, in the case when field data (Bo, Ce) and (Ce, Do) are extractedfrom areas of frame numbers 3 and 4 of the compressed 60i image signal(2:3) to form frame data C of the compressed 24p image signal, it is notpossible to apply the above-mentioned inverse conversion process. Inthis case, compressed field data (Bo, Ce) and (Co, De) constituting twoframes of frame number 3 and frame number 4 are respectively expanded.Hereinafter, the field data that have been expanded are referred to asthe expanded field data. Moreover, frame data to be combined from theexpanded field data are referred to as expanded frame data.

After the above-mentioned processes, expanded frame data C are composedfrom expanded field data (Ce) (field number 6) and expanded field data(Co) (field number 7). Then, the expanded frame data C are againcompressed to form compressed field data C. Since the inverse conversionprocess is required to execute such operations, the correspondingprocesses takes a long time, and the repeated compressing and expandingprocesses inevitably cause degradation in the image quality.

The objective of the present invention is to eliminate the necessity ofthe above-mentioned compressing/expanding processes that are requiredupon carrying out inverse conversion, to properly maintain the imagequality and to improve the processing rate.

DISCLOSURE OF THE INVENTION

In the present invention, upon recording an image of 4 frames as that of10 fields, the recording process is carried out not in a 2:3:2:3 format,but in a 2:3:3:2 format. By carrying out such a format conversionprocess, frame data A, B, C and D can be extracted in their current formfrom data areas of frame numbers, 1, 2, 4 and 5, upon carrying out aformat inversion-converting process.

With the process of the present invention, upon inverse-converting aformat, even when an image signal has been compressed on a frame basissimultaneously with the format conversion, the frame data can beextracted in their current form without the necessity of theexpanding/compressing processes, and subjected to a formatinverse-converting process. Thus, it becomes possible to preventdegradation in the image quality due to compressing/expanding processes,and also to shorten required the processing time.

The present invention is provided with an imaging device which picks upan image signal in an image format of 24 frames/second, a temporaryrecording device which temporarily records the image signal picked up bythe imaging device, and a 2:3:3:2 pull-down control device which readsthe image signal from the temporary recording device in an interlaceformat of 60 fields/second.

Upon reading first to fourth consecutive frame data of the image signalas first to tenth consecutive field data, the 2:3:3:2 pull-down controldevice carries out the controlling steps of: reading odd field data ofthe first frame as the first field data; reading even field data of thefirst frame as the second field data; reading odd field data of thesecond frame as the third and fifth field data; reading even field dataof the second frame as the fourth field data; reading odd field data ofthe third frame as the seventh field data; reading even field data ofthe third frame as the sixth and eighth field data; reading odd fielddata of the fourth frame as the ninth field data; and reading even fielddata of the fourth frame as the tenth field data.

With this arrangement, even in the case when a compressing process iscarried out on a latter stage of an output on a frame basis, it becomespossible to extract the image signal as picked up without degradation inthe image quality.

The present invention is also applicable to an image conversion systemwhich has an input device that inputs an image signal having an imageformat of 24 frames/second, in place of the imaging device. In thiscase, when an image that has been picked up in the image format of 24frames/second is input to an input device, the same effects as thosedescribed above are obtained.

The present invention is preferably provided with a recording devicewhich records an image signal that has been converted by a 2:3:3:2pull-down control device in an interlace system of 60 fields/second.This arrangement provides a higher degree of freedom in carrying imagedata. Moreover, the image data, recorded on a recording device, can beretrieved later without degradation in the image quality.

The present invention is preferably provided with a compressing devicewhich, with respect to the first to tenth field data read from thetemporary recording device, combines paired field data with each otherinto a piece of frame data, and then compresses the resulting data, andthe recording device records the image signal that has been compressedby the compressing device. Thus, in addition to the above-mentionedeffects, since the compressing process reduces the amount of data, itbecomes possible to provide a recording process that lasts a longertime.

In another aspect of the present invention, an image conversion systemis provided with: an input device to which a compressed image signal inan interlace system having a format of 60 fields/second, which has beencombined and compressed on a frame basis, is input; a frame-dataextracting control device which selectively extracts from the inputdevice the first, second, fourth and fifth frame data among the first tofifth frame data that form the compressed image signal and areconsecutively arranged with each other. With this arrangement, thecompressed image signal in the interlace system having an image formatof 60 fields/second to be input to the input device can be converted toan image signal having a progressive image format of 24/second withoutcausing degradation in the image quality and can be extracted.

In still another aspect of the present invention, an image-editingdevice is provided with: an input device to which a compressed imagesignal in an interlace system having a format of 60 fields/second, whichhas been combined and compressed on a frame basis, is input; aframe-data extracting control device which selectively extracts from theinput device the first, second, fourth and fifth frame data among thefirst to fifth frame data that form the compressed image signal and areconsecutively arranged with each other; a recording/reproducing devicewhich records/reproduces the compressed image signal extracted by theframe-data extracting control device; an image expanding device whichexpands the compressed image signal reproduced by therecording/reproducing device; an image output device which displays theexpanded image signal; and an editing device which edits the compressedimage signal reproduced from the recording/reproducing device on a framebasis. With this arrangement, the image signal input to the input deviceis extracted and edited without causing degradation in the imagequality.

Moreover, in still another aspect, the present invention is providedwith: an imaging device which picks up a first image signal in an imageformat of 24 frames/second; a temporary recording device whichtemporarily records the first image signal picked up by the imagingdevice; and a 2:3:3:2 pull-down control device which reads the firstimage signal from the temporary recording device as a second imagesignal having an image format of 30 frames/second.

The 2:3:3:2 pull-down control device carries out the controlling stepsof: converting field data located at odd fields of a frame correspondinga time-code value 4n of the first image signal to field data located atodd fields of a frame corresponding a time-code value 5n of the secondimage signal; converting field data located at even fields of a framecorresponding a time-code value 4n of the first image signal to fielddata located at even fields of a frame corresponding a time-code value5n of the second image signal; converting field data located at oddfields of a frame corresponding a time-code value 4n+1 of the firstimage signal to field data located at odd fields of a framecorresponding a time-code value 5n+1 of the second image signal;converting field data located at even fields of a frame corresponding atime-code value 4n+1 of the first image signal to field data located ateven fields of a frame corresponding a time-code value 5n+1 of thesecond image signal; converting field data located at odd fields of aframe corresponding a time-code value 4n+1 of the first image signal tofield data located at odd fields of a frame corresponding a time-codevalue 5n+2 of the second image signal; converting field data located ateven fields of a frame corresponding a time-code value 4n+2 of the firstimage signal to field data located at even fields of a framecorresponding a time-code value 5n+2 of the second image signal;converting field data located at odd fields of a frame corresponding atime-code value 4n+2 of the first image signal to field data located atodd fields of a frame corresponding a time-code value 5n+3 of the secondimage signal; converting field data located at even fields of a framecorresponding a time-code value 4n+2 of the first image signal to fielddata located at even fields of a frame corresponding a time-code value5n+3 of the second image signal; converting field data located at oddfields of a frame corresponding a time-code value 4n+3 of the firstimage signal to field data located at odd fields of a framecorresponding a time-code value 5n+4 of the second image signal; andconverting field data located at even fields of a frame corresponding atime-code value 4n+3 of the first image signal to field data located ateven fields of a frame corresponding a time-code value 5n+4 of thesecond image signal. In this arrangement, n is an integer of 0 to 5.

In this case, the present invention is preferably provided with arecording device that records the second image signal on a recordingmedium, and the recording device records the second image signal on therecording medium by a unit of 5 frames that corresponds to 1 sequence ofthe second image signal.

Preferably, the present invention is further provided with a recordingstart signal generator that generates a recording start signal that isset to a unit of 5 frames that corresponds to 1 sequence of the secondimage signal.

Preferably, the present invention is further provided with a time-codereading device that reads the time code of the second image signalrecorded on the recording medium, and the recording device starts arecording process of the second image signal in phase-synchronism withthe time code read by the time-code reading device.

Moreover, the recording device preferably records the second imagesignal based upon an interlace system of 60 fields/second.

Furthermore, the present invention is further provided with acompressing device which, with respect to the field data read from thetemporary recording device, combines paired field data with each otherinto apiece of frame data, and then compresses the resulting data, andthe recording device records the image signal that has been compressedby the compressing device.

With the above-mentioned arrangement, based upon the time codes attachedto the image signal and 1 sequence (2:3:3:2 sequence) of the imagesignal, a recording process of an image is started from a time-codeposition of the start frame 5n of 1 sequence. Then, the recordingprocess having 10 fields (5 frames) of the 2:3:3:2 pull-down system as 1sequence is repeated periodically. Thus, image-pickup and joiningimage-pickup recording processes can be carried out with the 2:3:3:2pull-down conversion system being maintained.

Moreover, in the case when an extracting process, which extracts acompressed image signal recorded on a 60i image format as an imagesignal having a 24p image format and which is a purpose of the 2:3:3:2conversion system, is carried out, a thinning process is executed byeliminating image data corresponding to a time code value of 5n+2 of thefirst image signal so that the compressed signal of 24p can be restored.

Further, even in the case when an output image signal is compressed andrecorded on a frame basis, the 24 frames as image-picked up can beextracted on a time-code basis without causing degradation in the imagequality.

Moreover, the recording start point can be determined inphase-synchronism with the time code of the image signal and 1 sequenceof the 2:3:3:2 pull-down conversion process.

Furthermore, a joining image-pickup process can be carried out inphase-synchronism with one sequence of the 2:3:3:2 pull-down conversionprocess.

In still another aspect of the present invention, an image conversionsystem is provided with an input device to which a first image signalhaving an image format of 24 frames/second is input, in place of animaging device which picks up the first image signal having the imageformat of 24 frames/second. This arrangement also provides the sameeffects as described above.

In still another aspect of the present invention, each of an imageconversion system and an image-editing device is provided with: an inputdevice to which a compressed image signal in an interlace system havinga format of 60 fields/second, which has been combined and compressed ona frame basis, is input and a frame-data extracting control device whichextracts pieces of frame data located at frame positions correspondingto time-code values of 5n, 5n+1, 5n+3 and 5n+4 (n: an integer of 0 to 5)from the input device.

In this case also, it is possible to obtain the effect that the inputimage signal is extracted on a time-code basis without degradation inthe image quality.

In still another aspect, the present invention is provided with aswitching device which switches control operations of the reading devicebetween the 2:3:3:2 pull-down control device and the 2:3:2:3 pull-downcontrol device.

Moreover, the present invention is provided with a switching devicewhich switches control operations of the reading device among the2:3:3:2 pull-down control device, the 2:3:2:3 pull-down control deviceand the 2:2:2:4 pull-down control device.

In this case, it becomes possible to properly use various kinds of imageconversion systems in a separate manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram that shows a structure of embodiment 1 of thepresent invention.

FIG. 1B is a block diagram that shows an essential portion of a modifiedexample of embodiment 1.

FIG. 2 is a schematic drawing that shows a relative relationship betweena 2:3:3:2 pull-down control process and an image-pickup recording unitin embodiment 1.

FIG. 3 is a schematic drawing that shows a relative relationship betweena 2:2:3:3 pull-down control process and an image-pickup recording unit.

FIG. 4 is a schematic drawing that shows a relative relationship betweena 3:3:2:2 pull-down control process and an image-pickup recording unit.

FIG. 5 is a schematic drawing that shows a relative relationship betweena 2:2:2:4 pull-down control process and an image-pickup recording unit.

FIG. 6 is a block diagram that shows a structure of embodiment 2 of thepresent invention.

FIG. 7 is a schematic drawing that shows a relative relationship betweena 2:3:3:2 pull-down control process and an image-pickup recording unitin embodiment 2.

FIG. 8 is a schematic drawing that shows a state at the time of inverseconversion in embodiment 2.

FIG. 9 is a schematic drawing that shows a state at the time oftime-code conversion in embodiment 2.

FIG. 10 is a block diagram that shows a structure of an image conversionsystem which is a modified example of embodiment 2.

FIG. 11 is a block diagram that shows a structure of an image conversionsystem in embodiment 3 of the present invention.

FIG. 12 is a drawing that shows a specific conversion process in eachconversion system.

FIG. 13 is a drawing that shows a structure of an image inverseconversion system that forms a pair together with an imaging system ofembodiment 3 of the present invention.

FIG. 14 is a drawing that shows an example of an image conversionsystem.

BEST MODES FOR CARRYING OUT THE INVENTION Embodiment 1

FIG. 1A is a block diagram that shows an image-editing system ofembodiment 1 of the present invention. In this figure, arrows connectingrespective blocks indicate processing directions of signals. Symbols,such as 24p and 60i, attached to the arrows respectively indicate thecorresponding image formats of image signals flowing through thecorresponding positions of the arrows, that is, 24p format (progressiveimage format of 24 frames/second) and 60i format (interlace image formatof 60 fields/second). Parentheses attached to 24p and 60i indicate thatthe image signal flowing through the corresponding arrow position hasbeen compressed.

This image-editing system is provided with an imaging system and animage-editing device. The imaging system is provided with an imagingdevice 11, a temporary recording device 12, an image compressing device13, a recording device 14, a 2:3:3:2 pull-down control device 15 and anoutput device 16.

The image-editing device is provided with an input device 17, arecording/reproducing device 18, an image expanding device 19, an imageoutput device 110, a frame data extracting control device 111 and anediting device 112. The image-editing device includes an imageconversion system. The image conversion system is constituted by theinput device 17 and the frame data extracting control device 111.

First, the following description discusses operations of the imagingsystem. The imaging device 11 picks up an image in a 24p image format,that is, an image format of 24 frames/second, through sequentialscanning processes, and outputs the resulting image. The 24p imagesignal, output from the imaging device 11, is successively sent to asequential temporary recording device 52. In the present embodiment,these consecutive frame data constituting the 24p image signal arereferred to as frame data A, B, C, D . . .

The 24p image signal, output from the imaging device 11, is subjected toa 2:3:3:2 pull-down conversion process in a 4-frame cycle. The 2:3:3:2pull-down conversion process, which is a conversion process thatfeatures the present invention, is controlled by the 2:3:3:2 pull-downcontrol device 15. Upon 2:3:3:2 pull-down conversion process by the2:3:3:2 pull-down control device 15, the temporary recording device 12temporarily records the image signal that is being processed. Thetemporary recording device 12 is installed so as to allow the 2:3:3:2pull-down control device 15 to carry out the 2:3:3:2 pull-downconversion process while offsetting a time lag between the writingtiming of the 24p image signal and the reading timing of the 60i imagesignal.

The 2:3:3:2 pull-down control device 15 writes the 24p image signaloutput from the imaging device 11 in the temporary recording device 12successively as consecutive frame data. The 2:3:3:2 pull-down controldevice 15 reads the 24p image signal written in the temporary recordingdevice 12 in synchronized reading timing with the 60i image signal withthe 24p image signal being decomposed into field data. Upon reading out,the 2:3:3:2 pull-down control device 15 controls the field data so as tobe arranged in the image format of the 60i image signal.

Referring to FIG. 2, the 2:3:3:2 pull-down conversion process to becarried out by the imaging system is explained in detail. The 2:3:3:2pull-down control device 15 writes frame data of the 24p image signaloutput by the imaging device 11 in the temporary recording pat 12. Inthis state, after decomposing the frame data recorded on the temporaryrecording device 52 into field data, the 2:3:3:2 pull-down controldevice 15 reads the resulting data in synchronized image timing with the60i image signal. In this case, the image timing of the 60i image signalis synchronized with the image timing of the 24p image signal. Thefollowing description discusses the reading control in detail. In FIG.2, symbol A attached to the 24p image signal indicates a first frame.Symbol B indicates a second frame. Symbol C indicates a third frame.Symbol D indicates a fourth frame. The field numbers 1 to 10, attachedto the 60i image signal, indicate respective storing areas of the firstto tenth field data.

First, in the former half timing of frame number 1 of the 60i imagesignal, field data (Ao) consisting of odd lines of frame data A of the24p image signal is read from the temporary recording device 12 throughan interlace process (jump scanning). Next, in the latter half timing offrame number 1 of the 60i image signal, field data (Ae) consisting ofeven lines of frame data A of the 24p image signal is read from thetemporary recording device 12 through the interlace process.

In the timing of frame number 2 of the 60i image signal, frame data b ofthe 24p image signal is read from the temporary recording device 12while being decomposed into field data (Bo, Be). At this time, thereading control is carried out in the same manner as the control inframe data A.

In the former half timing of frame number 3 of the 60i image signal,field data (Bo) consisting of odd lines of frame data b of the 24p imagesignal is read from the temporary recording device 12 through aninterlace process. In the latter half timing of frame number 3 of the60i image signal, field data (Ce) consisting of even lines of frame dataC of the 24p image signal is read from the temporary recording device 12through the interlace process.

In the timing of frame number 4 of the 60i image signal, frame data C ofthe 24p image signal is read from the temporary recording device 12while being decomposed into field data (Co) and (Ce). At this time, thereading control is carried out in the same manner as the control inframe data A.

In the timing of frame number 5 of the 60i image signal, frame data d ofthe 24p image signal is read from the temporary recording device 12while being decomposed into field data (Do) and (De). At this time, thereading control is carried out in the same manner as the control inframe data A.

The above-mentioned operations are periodically repeated in a 4-framecycle of the 24p image signal.

Since the frame data constituting the 24p image signal is read out fromthe temporary recording device 12 in the order as described above whilebeing decomposed into field data so that a 60i image signal isgenerated. The 60i image signal thus generated is successively sent tothe image compressing device 13.

After combining the odd field data (o) and the even field data (e)constituting the respective pieces of frame data of the 60i image signalinto one piece of frame data, the image compressing device 13 compressesthe data respectively on a frame-unit basis. With respect to the framecompressing method, the generally-used DV compressing method can beused.

The compressed 60i image signal, compressed in the image compressingdevice 13, is sent to the recording device 14 and is recorded on arecording medium such as a magnetic tape or an optical disk. Thecompressed 60i image signal is simultaneously sent from the imagecompressing device 13 to the output device 16, and externally output.

With respect to the format used for outputting the compressed data, thegenerally-used IEEE1394 format can be used. Here, the compressed 60iimage signal to be recorded on the recording device 14 can be extractedfrom the recording medium later in the recording device 14, and outputfrom the output device 16.

Next, the inverse conversion process to be carried out by theimage-editing device is explained. The inverse conversion process is aprocess which inversely converts the compressed 60i image signal to acompressed 24p image signal.

The compressed 60i image signal, output from the output device 16 of theimage editing device is input to the input device 17 of theimage-editing device. The compressed 60i image signal to be input to theinput device 17 is controlled by the frame data extracting controldevice 111 in its recording process, and recorded on a recording mediumby the recording/reproducing device 18. The recording control of theframe data extracting control device 111 is carried out in the followingmanner.

The frame data extracting control device 111 successively extractspieces of compressed frame data (Ao, Ae), (Bo, Be), (Co, Ce), (Do, De),. . . that are located at frame numbers 1, 2, 4, 5, . . . from whichframe number 5n−2 (n: natural number) is excluded, from the compressed60i image signal to be input to the input device 17.

The frame data extracting control device 111 recognizes the extractedcompressed frame data as compressed frame data of the compressed 24pimage signal, and outputs these frame data to the recording/reproducingdevice 18 as a 24p image signal. The recording/reproducing device 18records the input frame data on a recording medium in the 24p imageformat.

In this case, the compressed frame data, located at frame number 1, isframe data A of the compressed 60i image signal. Here, the compressedframe data corresponding to one frame of the compressed 60i image signalis identical to the compressed frame data corresponding to one frame ofthe compressed 24p image signal in the data format thereof. For thisreason, the compressed frame data, located at frame number 1, to beextracted from the compressed 60i image signal is recorded on therecording medium in the recording/reproducing device 18 as thecompressed frame data A of the compressed 24p image signal withoutdegradation in the image quality. In the same manner, pieces ofcompressed frame data, located at frame numbers 2, 4 and 5 of thecompressed 60i image signal are recorded on the recording medium in therecording/reproducing device 18 as the compressed frame data b, C and Dof the compressed 24p image signal without degradation in the imagequality. The compressed frame data, located at frame number 3 of thecompressed 60i image signal, is read, but ignored.

Next, editing processes to be carried out in the image-editing deviceare explained. Upon carrying out the editing processes, first, therecording/reproducing device 18 reproduces the compressed 24p imagesignal. The reproduced compressed 24p image signal is subjected to anexpanding process in the image expanding device 19 to be returned to anon-compressed 24p image signal. The 24p image signal, returned to thenon-compressed state, is sent to the image output device 110, anddisplayed as an image. With respect to the image output device 110, forexample, a display of a personal computer is used.

The user carries out editing processes while viewing an image displayedon the image output device 110. More specifically, the user specifies anediting start point and an editing terminal point of the image in theimage editing device. The user specifies the editing start point and theediting terminal point in the same manner with respect to a plurality ofimage portions. Upon receipt of these processes, the image-editingdevice combines the image portions, and the resulting image is againrecorded on the recording medium by the recording/reproducing device 18.Thus, the editing processes are completed. In this case, the editingdevice 112 records the editing start points, editing terminal points andthe order of the sequences, and based upon the record, the imageportions thus combined are displayed continuously on the image outputdevice 110.

Here, the above-mentioned explanation has been given by exemplifying the2:3:3:2 format as a format used for converting continuous 4 frames tocontinuous 10 fields. However, in addition to this, with respect to theformat which allows the compressed frame data, as it is, to be extractedon its frame unit basis, a 2:2:3:3 pull-down conversion format, shown inFIG. 3, and a 3:3:2:2 pull-down conversion format, shown in FIG. 4, arelisted.

These two pull-down conversion formats provide the same effects as the2:3:3:2 pull-down conversion format shown in FIG. 2. In the case whenthe 2:3:2:3 pull-down conversion format, which has been currently widelyused, is changed in its format, the 2:3:3:2 pull-down conversion formatonly needs to be changed in its one field among 10 fields, that is, onlyfield data corresponding to field number 8; therefore, this format issuperior in this point.

Additionally, the 2:2:2:4 pull-down conversion format, shown in FIG. 5,also provides the same effect. However, in this pull-down conversionformat, upon reproducing an image, the frame data, located at frameposition of “4” of the 24p image signal is placed in an overlappedmanner at continuous frame positions in the 60i image signal; therefore,the resulting disadvantage is that movements in the image becomediscontinuous, causing an instantaneous unnatural stopped image.

In contrast, in the 2:3:3:2 pull-down conversion format, the length offrame data A, B, C and D of the 24p image signal upon picking up animage corresponds to 2 fields (1 frame) or 3 fields (1.5 frames) in the60i image signal after the pull-down conversion so that it is possibleto avoid the same frame data from being placed in an overlapped mannerat continuous frame positions. The resulting advantage is that themovements of the image are continuous and smooth, and appear to benatural movements.

In the above-mentioned embodiment 1, the present invention is applied toan image-editing system provided with an imaging system. In addition tothis arrangement, as shown in FIG. 1B, embodiment 1 may be applied to animage-editing system provided with an image conversion system to which a24p image signal is input from an outside device, in the same manner.The image-editing device forming this image-editing system is the sameas the one shown in FIG. 1A. For this reason, in FIG. 1B, only the imageconversion system is disclosed. The basic structure of this imageconversion system is the same as that of the imaging system shown inFIG. 1A. The only difference from the one shown in FIG. 1A is that, inplace of the imaging device 11, an input device 20 to which a 24p imagesignal is input from outside is placed therein.

Embodiment 2

In general, in the imaging system, recording start points and recordingterminal points are set on a 1-frame basis. For this reason, in the casewhen a joining image-pickup recording process is carried out on a1-frame basis while the 2:3:3:2 pull-down conversion process and thecompressing process are carried out simultaneously, it is necessary tomaintain the data format of the 2:3:3:2 pull-down conversion system.

Moreover, when the 2:3:3:2 pull-down conversion process is widely used,sometimes there are cases in which a picked-up 24p image signal isrecorded on a recording medium on which a normal 60i image signal hasbeen recorded, and a joining image-pickup recording process of a 60iimage signal that has been subjected to a 2:3:3:2 pull-down conversionprocess is carried out thereon. In this case, on the time code basis, itis necessary to maintain time continuity between the elapsed time on thenormal 60i image signal and the elapsed time on the 60i image signalthat has been subjected to the 2:3:3:2 pull-down conversion process.

The present embodiment provides an image-editing system that satisfiesthis requirement.

Referring to FIGS. 6 to 11, the following description discusses thepresent embodiment. FIG. 6 is a block diagram that shows a structure ofan image-editing system in accordance with the present embodiment. Thesystem structure of FIG. 6 is basically the same as the one shown inFIG. 1A. For this reason, the same parts are indicated by the samereference numerals, and the description thereof is omitted. Moreover, inthese drawings, the time code of the 24p image signal is indicated as24pTC, and the time code of the 60i image signal is indicated as 60iTC.

An imaging system forming this image-editing system is provided with animaging device 11, a temporary recording device 12, an image compressingdevice 13, an output device 16, a time-code reading device 21, a 2:3:3:2pull-down control device 22, a recording start signal generator 23 and arecording/reproducing device 24. Moreover, the temporary recordingdevice 12 of the present embodiment generates a 60i servo referencesignal, and supplies the signal to a cylinder head 10.

An image-editing device forming this image-editing system is providedwith an input device 17, a recording/reproducing device 18, an imageexpanding device 19, a frame-data-extracting control device 111, anediting device 112, an image output device 110, a time-code converter130, and a time-code output device 125.

First, the following description discusses operations of the imagingsystem. The time-code reading device 21 reads 60iTC from the 60i imagesignal recorded on a recording medium 100. This reading process iscarried out in synchronism with a 60i servo reference signal. Thetime-code reading device 21 supplies the 60iTC thus read to the 2:3:3:2pull-down control device 22. The 2:3:3:2 pull-down control device 22reads frame data of the 24p image signal recorded on the temporaryrecording device 12. This reading process is carried in a manner so asto make the phase of the image timing of the 60i image signal and thephase of the frame timing of 60iTC coincident with each other.

Next, the following description discusses the reading control carriedout by the 2:3:3:2 pull-down control device 22 in detail. Here, thereading control refers to a controlling process used for reading a 24pimage signal from the temporary recording device 12. In the followingexplanation, 60iTC is defined to be code-arranged in a manner so as tosuccessively repeat 60iTC (5n), 60iTC (5n+1), 60iTC (5n+2), 60iTC (5n+3)and 60iTC (5n+4) as 60iTC. Here, n represents an integer from 0 to 5.

First, in the former half timing of 60iTC (5n), field data (Ao)consisting of odd lines of frame data A of the 24p image signal are readfrom the temporary recording device 12 through an interlace process(jump scanning). Next, in the latter half timing of 60iTC(5n), fielddata (Ae) consisting of even lines of frame data A of the 24p imagesignal are read from the temporary recording device 12 through theinterlace process.

In the same manner, in the timing of 60iTC (5n+1), pieces of field data(Bo), (Be) in frame B are read from the temporary recording device 12.

Next, in the former half timing of 60iTC(5n+2), field data (Bo)consisting of odd lines of frame data b are read from the temporaryrecording device 12 through an interlace process. In the latter halftiming of 60iTC(5n+2), field data (Ce) consisting of even lines of framedata Care read from the temporary recording device 12 through theinterlace process.

Next, in the timing of 60iTC (5n+3), pieces of field data (Co), (Ce) offrame C are read from the temporary recording device 12. The readingprocess is carried out in the same manner as 60iTC (5n).

Next, in the timing of 60iTC (5n+4), pieces of field data (Do), (De) offrame D are read from the temporary recording device 12. The readingprocess is carried out in the same manner as 60iTC (5n).

The above-mentioned processes are periodically repeated in a 4-framecycle of the 24p image signal (24pTC). Thus, the 24p image signal,temporarily recorded on the temporary recording device 12, is convertedto a 60i image signal in a state so as to correspond to 60iTC read fromthe recording medium 100 by the time-code reading device 21.

The 60i image signal after the conversion, output from the temporaryrecording device 12, is successively sent to the image compressingdevice 13 in phase-synchronism with the time-code frame reference of therecording medium 100. The image compressing device 13 carries out thefollowing processes on the 60i image signal input thereto. In the 60iimage signal, 2 pieces of field data consisting of consecutive odd fieldand even field are combined into 1 piece of frame data. Further, theimage compressing device 13 compresses (in-frame compression) thecombined frame data on a frame basis. The compressing process is carriedout in the same manner as embodiment 1.

The compressed 60i image signal, compressed by the image compressingdevice 13, is supplied to the recording/reproducing device 24. At thistime, the 2:3:3:2 pull-down control device 22 simultaneously supplies60iTC to the recording start signal generator 23. The recording startsignal generator 23 generates a recording start signal from the supplied60iTC, and supplies the resulting signal to the recording/reproducingdevice 24. The recording start signal generator 23 sets a recordingstart point in the recording start signal based upon the conversioncycle of the 2:3:3:2 pull-down conversion process. More specifically,the recording start signal generator 23 makes the recording start pointsynchronized with the conversion start point (60iTC (5n)) of the 2:3:3:2pull-down conversion process.

Based upon the recording start signal supplied thereto, therecording/reproducing device 24 records the compressed 60i image signaland the 60iTC on another recording medium, with the two signals beingmade in association with each other. With respect to another recordingmedium, for example, a magnetic tape and an optical disk may be used.

Upon recording by the use of the recording/reproducing device 24, thecompressed 60i image signal is simultaneously sent to the output device16 together with 60iTC from the image compressing device 13, andexternally output as compressed image data.

With respect to the format used for outputting the compressed imagedata, for example, the IEEE1394 format is used. Here, the compressed 60iimage signal recorded on the recording device 24 can be reproduced fromthe recording medium later in the recording device 24, and output fromthe output device 16.

Next, the inverse conversion process to be carried out by theimage-editing device is explained. In this case, the inverse conversionprocess is a process which inversely converts the compressed 60i imagesignal to a compressed 24p image signal in the same manner as embodiment1.

The compressed 60i image signal, output from the output device 16 of theimage editing device, is input to the input device 17 of theimage-editing device. The compressed 60i image signal to be input to theinput device 17 is inversely converted into a 24p image signal, andfurther subjected to an expanding process. The inversely convertingprocess and expanding process are carried out by the frame-dataextracting control device 111, the recording/reproducing device 18 andthe image expanding device 19. These processes are the same as those ofembodiment 1; therefore, the explanation thereof is omitted.

Here, the time-code converter 130 extracts 60iTC from the compressed 60iimage signal input to the input device 17, and converts the signal to24pTC. The time-code converter 130 outputs the generated 24pTC to thetime-code output device 125. The time-code output device 125 converts24pTC to information (for example, display information) that isrecognized by the user, and outputs the resulting signal. With respectto the time-code output device 125, the image output device 122 may becompatibly used when display information is output. The user carries outediting processes while viewing images output by the image output device110 and time-code information output by the time-code output device 125.More specifically, the user specifies the starting point and terminalpoint of an image in the image-editing device based on a time-codebasis.

The user carries out the above-mentioned editing processes whilerecognizing the time-code information output by the time-code outputdevice 125 and image information displayed by the image output device122. Upon editing, the recording and editing processes of the 24p imagesignal are carried out, with the 24p image signal and 24pTC beingphase-synchronized with each other. More specifically, the editingdevice 112 records the editing start point, editing terminal point andthe order thereof, and while the image portions are displayed by theimage output device 110 based upon the record, a plurality of imageportions specified by the user are arranged; thus, the editing processesare completed. In this case, the editing start point and the editingterminal point are specified by the user on a 24pTC basis. Further, theuser carries out the above-mentioned editing processes while viewing animage on the image output device 110 and a time code on the time-codeoutput device 125.

The 24p editing signal that has been subjected to the editing process isagain recorded on the recording medium by the recording/reproducingdevice 18. The editing processes to be carried out by the image-editingdevice are basically the same as those explained in embodiment 1.

FIG. 7 is a schematic drawing that shows a relative relationship betweena 2:3:3:2 pull-down conversion process and an image-pickup recordingunit in accordance with the present embodiment. When the 24p imagesignal is converted to a 60i image signal by a 2:3:3:2 pull-downconversion process, the recording start signal generator 23 is made inphase-synchronism with 60iTC read from the recording medium 100 to set arecording start signal. The recording/reproducing unit 24 sets arecording start point (60iTC (5n)) based upon the recording start signalthus set, and starts a joining image-pickup recording process. Moreover,on a 60iTC frame basis, partial extracting and combining processes offrame data corresponding to the respective pieces of field data arecarried out from the compressed 24p image signal, in synchronism with60iTC (5n), 60iTC (5n+1), 60iTC (5n+2), 60iTC (5n+3) and 60iTC (5n 4).These processes have been already discussed in embodiment 1. Thus, whilethese processes are being periodically repeated, the resulting imagesignal is recorded on the recording/reproducing device 24 so that thejoining image-pickup recording process is carried out.

FIG. 8 is a schematic drawing that shows the operations of the framedata extracting control device 111 of the present invention. Uponinversely converting the compressed 60i image signal to a compressed 24pimage signal, based upon the 60iTC time-code criteria, pieces ofcompressed field data (Bo, Ce) corresponding to 60iTC (5n+2) are read,and ignored. Pieces of compressed field data (Ao, Ae), (Bo, Be), (Co,Ce) and (Do, De) corresponding to 60iTC(5n), 60iTC(5n+1), 60iTC(5n+3)and 60iTC (5n+4) (n=integer of 0 to 5) are converted to compressed framedata of the compressed 24p image signal corresponding to 24pTC(4n),24pTC(4n+1), 24pTC(4n+2) and 24pTC(4n+3). Thus, it is possible toachieve a natural image conversion process with smooth movements beingmaintained.

The following description discusses a time-code converting operation(60iTC→24pTC) carried out by the time-code converter 130. The time-codeconverter 130 deletes 60iTC (2), (7), (12), (17), (22) and (27) thatcorrespond to 60iTC(5n+2), and extracts the rest of 60iTC (5n), 60iTC(5n+1), 60iTC (5n+3) and 60iTC(5n+4) (in which n is an integer of 0 to5). Thus, the time-code converter 130 generates 24pTC (4n), 24pTC(4n+1), 24pTC(4n+2) and 24pTC(4n+3) (in which n is an integer of 0 to5). The generated 24pTC is restored while being made phase-synchronizedwith the image. FIG. 9 shows a relative relationship between thetime-code converting operation (60iTC→24pTC) carried out by thetime-code converter 130 and the inversely converting operation from the24p image signal to the 60i image signal.

FIG. 10 shows a structure of an image conversion system that is amodified example of embodiment 2. This image conversion system isprovided with a temporary recording device 12, an image compressingdevice 13, a 2:3:3:2 pull-down control device 22, a recording startsignal generator 23, a recording/reproducing device 24 and an outputdevice 16, and these constituent parts are the same as those parts inthe imaging system of embodiment 2. In addition to the above-mentionedconstituent parts, the image conversion system is provided with a 24pimage signal input device 30 and a 24p time-code input device 31. The24p image signal input device 30 and the 24p time-code input device 31are parts that exert interface functions for receiving the 24p imagesignal and 24pTC from outside of the image conversion system. Theseprovide functions that replace the imaging device 11 and the time-codereading device 21 in the imaging system.

In the image conversion system, the 24pTC to be input to the 24ptime-code input device 31 needs to be converted to the 60iTC. Thistime-code converting operation is carried out by the 2:3:3:2 pull-downcontrol device 22. The time-code conversion is executed by adding60iTC(5n+2), that is, 60iTC(2), 60iTC(7), 60iTC(12), 60iTC(17),60iTC(22) and 60iTC(27), to 24pTC(4n), 24pTC(4n+1), 24pTC(4n+2) and24pTC(4n+3).

Additionally, in embodiment 2, the present invention is achieved by astructure in which one sequence of the 2:3:3:2 pull-down conversionprocess is used as a frame value. However, the present invention is alsoachieved by using a structure in which information of one sequence ofthe 2:3:3:2 pull-down conversion process is written in a user area ofthe recording medium.

Moreover, in embodiment 2, the present invention is achieved by usingthe 2:3:3:2 pull-down conversion process. In addition to this, thepresent invention is also achieved by using the 2:3:2:3 pull-downconversion processor the 2:2:2:4 pull-down conversion process.

Embodiment 3

As described above, the pull-down conversion process includes variousconversion formats such as the 2:3:3:2 pull-down conversion process,2:3:2:3 pull-down conversion process, 2:2:2:4 pull-down conversionprocess, 2:2:3:3 pull-down conversion process and 3:3:2:2 pull-downconversion process. Each of these conversion systems has its inherentadvantages, although it also has its inherent disadvantages. For thisreason, these conversion systems need to be used separately depending onpurposes of use of images.

The present invention provides an imaging system and an image conversionsystem which can properly use the various image conversion systems in aseparate manner.

FIG. 11 is a block diagram that shows a structure of an imaging systemof the present embodiment. After obtaining 24p image signals, thisimaging system converts the picked-up 24p image signal to the 60i imagesignal in accordance with any one of the conversion systems among the2:3:2:3 pull-down conversion process, 2:3:3:2 pull-down conversionprocess and 2:2:2:4 pull-down process.

This imaging system is provided with a CCD 42, an A/D converter 43, anRGB converter 44, a cinema gamma adjusting device 45, a noise eliminator46, an edge emphasizing device 47, a temporary recording device 48, apull-down control device 49, a reading device 50, a compressionprocessing device 51, a recording device 52 and a switching device 53.

The CCD 42 converts light that is directed from a subject into anelectric signal. The A/D converter 43 converts the electric signal intoa digital image signal. The A/D converter 43 reads the electric signalfrom the CCD 42 in an image format of 24 frames/second so that theelectric signal of the CCD 42 is converted to a digital image signalhaving the image format of 24 frames/second. The RGB converter 44converts the digital image signal to a digital RGB signal. The cinemagamma adjusting device 45 carries out a cinema gamma adjustment on thedigital RGB signal. The noise eliminator 46 carries out a noiseeliminating process on the digital RGB signal that has beencinema-gamma-adjusted. The edge emphasizing device 47 carries out anedge-emphasizing process on the digital RGB signal that has beensubjected to the noise-eliminating process. The digital RGB signalformed in this manner provides a 24p image signal. The temporaryrecording device 48 temporarily records the 24p image signal. Thetemporary recording device 48 is provided with a first field memory 48 aand a second field memory 48 b. The first field memory 48 a extractsfield data consisting of horizontal line signals placed at odd linepositions among the respective horizontal line signals constituting the24p image signal, and temporarily records the data. The second fieldmemory 48 b extracts field data consisting of horizontal line signalsplaced at even line positions among the respective horizontal linesignals constituting the 24p image signal.

The reading device 50 reads the respective field data temporarily storedin the first and second field memories 8 a and 8 b based upon anyone ofthe conversion systems of the (2:3:2:3 pull-down conversion system),(2:3:3:2 pull-down conversion system) and (2:2:2:4 pull-down conversionsystem).

The pull-down control device 49 controls the reading timing in which thereading device 50 reads the respective field data from the first andsecond field memories 8 a and 8 b based upon any one of the conversionsystems of the (2:3:2:3 pull-down conversion system), (2:3:3:2 pull-downconversion system), and (2:2:2:4 pull-down conversion system). Thedetailed descriptions of the respective conversion systems will be givenlater. Thus, the 60i image signal, which has been converted by any oneof the systems, is output from the temporary recording device 48.

The compression processing device 51 compresses the 60i image signalread from the temporary recording device 48 (first and second fieldmemories 48 a and 48 b). The recording device 52 records the 60i imagesignal that has been compressed in the compression processing device 10on a recording medium (video tape, hard disk device, optical disk,etc.), not shown.

The switching device 53 selects any one of the 2:3:2:3 pull-downconversion system, 2:3:3:2 pull-down conversion system and 2:2:2:4pull-down conversion system as the conversion system to be used forconverting the 24p video signal to the 60i image signal, and outputs theresulting command of selection to the pull-down control device 49. Theselection of the conversion system by the switching device 42 is carriedout, for example, through the switch (not shown) placed on an operationpanel (not shown) of the imaging system.

In the present embodiment, the imaging device is constituted by the CCD42, the A/D converter 43, the RGB converter 44, the cinema gammaadjusting device 45, the noise eliminator 0.46 and the edge-emphasizingdevice 47. The pull-down control device 49 includes the 2:3:2:3pull-down control device, the 2:3:3:2 pull-down control device and the2:2:2:4 pull-down control device.

The following description discusses an image-pickup operation carriedout by the imaging system.

Since the sequence of processes up to the edge-emphasizing process ofthe digital RGB signal carried out by the edge-emphasizing device 47 isthe same as that of the conventional device, the description of thesignal processing up to this point is omitted. The present imagingsystem is characterized by signal processing to be carried out on the24p image signal output from the edge emphasizing device 47.

In the present imaging system, upon converting the 24p image signal tothe 60i image signal, any one of the conversion systems of the 2:3:2:3pull-down conversion system, 2:3:3:2 pull-down conversion system and2:2:2:4 pull-down conversion system may be applied. First, the commandsignal indicating which conversion system to be used is input to theswitching device 13. The inputting process of the command signal iscarried out by the operator through, for example, a switch (not shown)attached to an operation panel (not shown) of the imaging system.

Upon receipt of the command input of the conversion system, theswitching device 13 outputs a command signal for the conversion systemto the pull-down control device 49. Upon receipt of the command signal,the pull-down control device 49 carries out a reading control on thereading device 50 based upon the specified conversion system.

The following explanation is given by exemplifying a case in which, inthe 24p image signal, pieces of consecutive first frame data (A) tofourth frame data (D) are converted to pieces of consecutive first fielddata (1) to tenth field data (10). Here, the first frame data (A) to thefourth frame data (D) in the 24p image signal are decomposed into oddfield data (Ao to Do) and even field data (Ae to De). The odd field data(Ao to Do) are temporarily recorded in the first field memory 48 a. Theeven field data (Ae to De) are temporarily recorded in the second fieldmemory 48 b. The odd field data (Ao to Do) and even field data (Ae toDe), temporarily recorded in the first and second field memories 48 aand 48 b, are read by the reading device 50 in accordance with apredetermined reading sequence to form the first field data (1) to thetenth field data (10).

The following description discusses the conversion operation in the casewhen the 2:3:3:2 pull-down conversion system is specified. In this case,the following reading control is given to the reading device 50 by thepull-down control device 49.

As shown in FIG. 12A, the odd field data (Ao) of the first frame data(A) are read as the first field data (1). The even field data (Ae) ofthe first frame data (A) are read as the second field data (2).

The odd field data (Bo) of the second frame data (B) are read as thethird field data (3). The even field data (Be) of the second frame data(B) are read as the fourth field data (4).

The odd field data (Bo) of the second frame data (B) are read as thefifth field data (5). The even field data (Ce) of the third frame data(C) are read as the sixth field data (6).

The odd field data (Co) of the third frame data (C) are read as theseventh field data (7). The even field data (De) of the fourth framedata (D) are read as the eighth field data (8).

The odd field data (Do) of the fourth frame data (D) are read as theninth field data (9). The even field data (De) of the fourth frame data(D) are read as the tenth field data (10).

The following description discusses the conversion operation in the casewhen the 2:3:3:2 pull-down conversion system is specified. In this case,the following reading control is given to the reading device 50 by thepull-down control device 49.

As shown in FIG. 12B, the odd field data (Ao) of the first frame data(A) are read as the first field data (1). The even field data (Ae) ofthe first frame data (A) are read as the second field data (2).

The odd field data (Bo) of the second frame data (B) are read as thethird field data (3). The even field data (Be) of the second frame data(B) are read as the fourth field data (4).

The odd field data (Bo) of the second frame data (B) are read as thefifth field data (5). The even field data (Ce) of the third frame data(C) are read as the sixth field data (6).

The odd field data (Co) of the third frame data (C) are read as theseventh field data (7). The even field data (Ce) of the third frame data(C) are read as the eighth field data (8).

The odd field data (Do) of the fourth frame data (D) are read as theninth field data (9). The even field data (De) of the fourth frame data(D) are read as the tenth field data (10).

The following description discusses the conversion operation in the casewhen the 2:2:2:4 pull-down conversion system is specified. In this case,the following reading control is given to the reading device 50 by thepull-down control device 49.

As shown in FIG. 12C, the odd field data (Ao) of the first frame data(A) are read as the first field data (1). The even field data (Ae) ofthe first frame data (A) are read as the second field data (2).

The odd field data (Bo) of the second frame data (B) are read as thethird field data (3). The even field data (Be) of the second frame data(B) are read as the fourth field data (4).

The odd field data (Co) of the third frame data (C) are read as thefifth field data (5). The even field data (Ce) of the third frame data(C) are read as the sixth field data (6).

The odd field data (Do) of the fourth frame data (D) are read as theseventh field data (7). The even field data (De) of the fourth framedata (D) are read as the eighth field data (8).

The odd field data (Do) of the fourth frame data (D) are read as theninth field data (9). The even field data (De) of the fourth frame data(D) are read as the tenth field data (10).

Here, the first to tenth field data (1 to 10), generated by theabove-mentioned conversion processes, correspond to the following fielddata in frames having consecutive sequence numbers (0 to 4) in the 60iimage signal.

The first field data (1) forms odd field data of the frame havingsequence number (0). The second field data (2) forms even field data ofthe frame having sequence number (0).

The third field data (3) forms odd field data of the frame havingsequence number (1). The fourth field data (4) forms even field data ofthe frame having sequence number (1). The fifth field data (5) forms oddfield data of the frame having sequence number (2). The sixth field data(6) forms even field data of the frame having sequence number (2).

The seventh field data (7) forms odd field data of the frame havingsequence number (3). The eighth field data (8) forms even field data ofthe frame having sequence number (3).

The ninth field data (9) forms odd field data of the frame havingsequence number (4). The tenth field data (10) forms even field data ofthe frame having sequence number (4).

After the 24p image signal has been converted to a 60i image signal inaccordance with the corresponding conversion system, the converted 60iimage signal is compressed by the compression processing device 51. The60i image signal thus compressed is recorded on a recording medium (notshown) in the recording device 52. Here, the recording device 52 hasconversion-system information input thereto from the pull-down controldevice 49, and the recording device 52 records the conversion-systeminformation of the 60i image signal being recorded, on the recordingmedium. The conversion-system information is written in, for example,the user's bit area of the 60i image signal.

As described above, the imaging system converts the 24p image signal toa 60i image signal in accordance with a desired one of the conversionsystems, and records the resulting signal; and the respective conversionsystems have the following advantages and disadvantages.

2:3:2:3 Pull-Down Conversion System

[Advantages]

This conversion system is a conversion system that mainly aims at animage signal that is subjected to field compression, and in thisconversion system, pieces of consecutive field data in the 24p imagesignal are evenly distributed and placed over the respective fields ofthe 60i image signal; therefore, this system is suitably used forconverting image signals containing images having active movements suchas movies.

[Disadvantages]

Since this conversion system aims at an image signal that is subjectedto field compression, it takes a long period of time in converting animage signal that has been frame-compressed.

Upon converting an image signal that has been frame-compressed, thissystem causes comparatively large degradation in image quality due tocompressing/expanding processes.

More specifically, the conversion generates pieces of field data thatare not continuous in terms of time, and since the amount of conversionof discontinuous data in terms of time is greater as compared to theother conversion systems, this system becomes most unsuitable in thecase when a slow reproducing process or a still-image reproducingprocess is carried out after conversion.

2:3:3:2 Pull-Down Conversion System

[Advantages]

Upon converting the 60i image signal to a 24p image signal, theconversion is made by omitting the third frame so that no degradation inimage quality occurs due to compressing/expanding processes.

Pieces of consecutive field data in the 24p image signal are evenlydistributed and placed over the respective fields of the 60i imagesignal; therefore, this system is suitably used for converting imagesignals containing images having active movements such as movies.

[Disadvantages]

Strictly speaking, the conversion causes field images that arediscontinuous in terms of time, and since the amount of conversion ofdiscontinuous data in terms of time is greater, although not so great asthat of the 2:3:2:3 pull-down conversion system, this system isunsuitable in the case when a slow reproducing process or a still-imagereproducing process is carried out after conversion.

2:2:2:4 Pull-Down Conversion System

[Advantages]

This conversion system is a conversion system that mainly aims at animage signal that is subjected to frame compression, and in the case ofan image signal that has been frame-compressed, this system carries outthe processes without requiring any processing time.

Upon converting an image signal that has been frame-compressed, thissystem causes no degradation in image quality due tocompressing/expanding processes.

This system generates the least amount of field images that arediscontinuous in terms of time; therefore, this system is suitably usedin the case when a slow reproducing process or a still-image reproducingprocess is carried out after conversion.

[Disadvantages]

Since two frames of the five frames are constituted by the same image,this system is unsuitable for conversion of image signals that containimages having active movements.

In the imaging system 1 of the present embodiment, by reviewing thestate of an image to be picked up based upon the above-mentionedadvantages and disadvantages of the respective conversion systems, anoptimal conversion system for the image signal to be picked up can beselected.

In the above-mentioned embodiment 3, the present invention is applied toan imaging system provided with a recording device 52; however, thepresent invention can of course be applied to an imaging system which isnot provided with a recording device 52, and externally outputs the 60iimage-pickup signal as converted so that it is recorded on a recordingmedium of an external recording device.

Moreover, in the above-mentioned embodiment 3, the present invention isapplied to an imaging system provided with an imaging device; however,in addition to this arrangement, the present invention can be applied toan image conversion system in which no imaging device is installed. Inthis case, the image conversion system refers to a device in which theinput 24p image signal is converted to a 60i image signal based upon anydesirably selected one of the conversion systems including the 2:3:2:3pull-down conversion system, 2:3:3:2 pull-down conversion system and2:2:2:4 pull-down conversion system.

As shown in FIG. 11, this image conversion system has an arrangement inwhich the CCD 42, the A/D converter 43, the RGB converter 44, the cinemagamma adjusting device 45, the noise eliminator 46 and theedge-emphasizing device 47 are omitted from the construction of theimaging system, with an input device 54 to which the 24p image signal isinput being added thereto, and with respect to the converting processesof images, completely the same processes as those of the imaging systemare carried out.

Moreover, in the above-mentioned imaging system and image conversionsystem, the picked-up 24p image signal is converted to a 60i imagesignal based upon any desirably selected one of the conversion systemsincluding the 2:3:2:3 pull-down conversion system, 2:3:3:2 pull-downconversion system and 2:2:2:4 pull-down conversion system. The presentinvention is not intended to be limited to this arrangement, and thepicked-up 24p image signal may be converted to a 60i image signal basedupon either desired one of the 2:3:2:3 pull-down conversion system andthe 2:3:3:2 pull-down conversion system.

In the same manner, the picked-up 24p image signal may be converted to a60i image signal based upon either desired one of the 2:3:2:3 pull-downconversion system and the 2:2:2:4 pull-down conversion system.

Moreover, the picked-up 24p image signal may be converted to a 60i imagesignal based upon either desired one of the 2:3:3:2 pull-down conversionsystem and the 2:2:2:4 pull-down conversion system.

Referring to FIG. 13, the following description discusses an imageinverse conversion device in which the 60i image signal formed in theabove-mentioned imaging system (60i image signal derived from theconversion of the 24p image signal carried out based upon a desiredconversion system) is inversely converted to the 24p image signal.

This image inverse conversion device is provided with an input device61, a switch 62, an expanding device 63, a first frame-extracting device64A, a second frame-extracting device 64B, a compressing device 65 andan extracting control device 66.

Here, in order to design this image inverse conversion device as animage-editing device, in addition to the above-mentioned devices, anediting device 67, a recording device 68, an expanding device 69 and animage output device 70 are installed therein. FIG. 13 shows a structureof an image conversion system, which functions as an image-editingdevice.

The following description discusses the operation of this image inverseconversion device. When a 60i image signal is input to the input device61, the input device 61 reads the conversion system information recordedon the user's bit or the like of the image signal, and outputs theconversion system information to the frame-extracting control device 66.

Upon receipt of the conversion system information, the extractingcontrol device 66 switches the switch 62 in accordance with theconversion system. More specifically, in the case when the 60i imagesignal to be input has been converted through the 2:3:2:3 pull-downconversion system, the signal needs to be once subjected to an expandingprocess. In contrast, in the case when it has been converted through the2:3:3:2 pull-down conversion system or the 2:2:2:4 pull-down conversionsystem, the signal need not be subjected to the expanding process.

When the conversion system information indicating the conversion systemis input to the extracting control device 66 from the input device 61,the extracting control device 66 connection-controls the switch 62 inthe following manner, by taking these features of the respectiveconversion systems into consideration. In other words, the extractingcontrol device 66 carries out the connection-controlling process bywhich the input device 61 and the expanding device 63 are connected bythe switch 62. Here, upon receipt of the conversion system informationindicating the 2:3:3:2 pull-down conversion system or the 2:2:2:4pull-down conversion system from the input device 61, the extractingcontrol device 66 connection-controls the switch 62 in the followingmanner. The extracting control device 66 carries out a connectioncontrol so that the input device 61 is connected to the secondframe-extracting device 64B through the switch 62.

As described above, for each of the conversion systems, the signaltransmission corresponding to the conversion system is carried out.

Next, the following description discusses a case in which a 60i imagesignal that has been converted through the 2:3:2:3 pull-down conversionsystem is input.

In this case, the 60i image signal is input to the expanding device 63through the switch 62, and expanded therein. The 60i image signal, thusexpanded, is input to a first frame-extracting device 64A. The firstframe-extracting device 64A has conversion-system informationpreliminarily input thereto from the extracting control device 66, andcarries out an inverse conversion process on the input 60i image signalin accordance with the specified conversion system (2:3:2:3 pull-downconversion system). The first frame-extracting device 64A carries out aninverse conversion process to the conversion process shown in FIG. 12Aso that the 60i image signal is inversely converted to a 24p imagesignal. More specifically, the inverse conversion process is carried outin the following manner.

In this case, as shown in FIG. 12A, the first field data (1) isextracted as the odd field data (Ao) of the first frame data (A). Thesecond field data (2) is extracted as the even field data (Ae) of thefirst frame data (A).

The third field data (3) is extracted as the odd field data (Bo) of thesecond frame data (B). The fourth field data (4) is extracted as theeven field data (Be) of the second frame data (B).

The fifth field data (5) is extracted as the odd field data (Bo) of thesecond frame data (B). The sixth field data (6) is extracted as the evenfield data (Ce) of the third frame data (C).

The seventh field data (7) is extracted as the odd field data (Co) ofthe third frame data (C). The eighth field data (8) is extracted as theeven field data (De) of the fourth frame data (D).

The ninth field data (9) is extracted as the odd field data (Do) of thefourth frame data (D). The tenth field data (10) is extracted as theeven field data (De) of the fourth frame data (D).

As described above, the first frame-extracting device 64A extracts imagesignals from the 60i image signal in a predetermined extracting order sothat a 24p image signal is generated. The 24p image signal, thusgenerated (inversely converted), is input to the compressing device 65,and compressed therein. The 24p image signal is compressed to form animage signal having a normal image format.

Next, the following description discusses a case in which a 60i imagesignal that has been converted through the 2:3:3:2 pull-down conversionsystem is input.

In this case, the 60i image signal is input to a second frame-extractingdevice 64B through a switch 62. The second frame-extracting device 64Bhas conversion-system information preliminarily input thereto from theextracting control device 66, and carries out an inverse conversionprocess on the input 60i image signal in accordance with the specifiedconversion system (2:3:3:2 pull-down conversion system). The secondframe-extracting device 64B carries out an inverse conversion process tothe conversion process shown in FIG. 12B so that the 60i image signal isinversely converted to a 24p image signal. More specifically, theinverse conversion process is carried out in the following manner.

In this case, as shown in FIG. 12B, the first field data (1) isextracted as the odd field data (Ao) of the first frame data (A). Thesecond field data (2) is extracted as the even field data (Ae) of thefirst frame data (A).

The third field data (3) is extracted as the odd field data (Bo) of thesecond frame data (B). The fourth field data (4) is extracted as theeven field data (Be) of the second frame data (B).

The fifth field data (5) is extracted as the odd field data (Bo) of thesecond frame data (B). The sixth field data (6) is extracted as the evenfield data (Ce) of the third frame data (C).

The seventh field data (7) is extracted as the odd field data (Co) ofthe third frame data (C). The eighth field data (8) is extracted as theeven field data (Ce) of the third frame data (C).

The ninth field data (9) is extracted as the odd field data (Do) of thefourth frame data (D). The tenth field data (10) is extracted as theeven field data (De) of the fourth frame data (D).

As described above, the second frame-extracting device 64B extractsimage signals from the 60i image signal in a predetermined extractingorder so that a 24p image signal is generated. The 24p image signal isallowed to form an image signal having a normal image format.

Next, the following description discusses a case in which a 60i imagesignal that has been converted through the 2:2:2:4 pull-down conversionsystem is input.

In this case, the 60i image signal is input to the secondframe-extracting device 64B through the switch 62. The secondframe-extracting device 64B has conversion-system informationpreliminarily input thereto from the extracting control device 66, andcarries out an inverse conversion process on the input 60i image signalin accordance with the specified conversion system (2:2:2:4 pull-downconversion system). More specifically, the first frame-extracting device64A carries out an inverse conversion process to the conversion processshown in FIG. 12C so that the 60i image signal is inversely converted toa 24p image signal.

In this case, as shown in FIG. 12C, the first field data (1) isextracted as the odd field data (Ao) of the first frame data (A). Thesecond field data (2) is extracted as the even field data (Ae) of thefirst frame data (A).

The third field data (3) is extracted as the odd field data (Bo) of thesecond frame data (B). The fourth field data (4) is extracted as theeven field data (Be) of the second frame data (B).

The fifth field data (5) is extracted as the odd field data (Co) of thethird frame data (C). The sixth field data (6) is extracted as the evenfield data (Ce) of the third frame data (C).

The seventh field data (7) is extracted as the odd field data (Do) ofthe fourth frame data (D). The eighth field data (8) is extracted as theeven field data (De) of the fourth frame data (D).

The ninth field data (9) is extracted as the odd field data (Do) of thefourth frame data (D). The tenth field data (10) is extracted as theeven field data (De) of the fourth frame data (D).

As described above, the second frame-extracting device 64B extractsimage signals from the 60i image signal in a predetermined extractingorder so that a 24p image signal is generated. The 24p image signal,thus generated (inversely converted) is allowed to form an image signalhaving a normal image format.

In this manner, the 60i image signal that has been converted through the2:3:2:3 pull-down conversion system is subjected toexpanding/compressing processes, when inversely converted to a 24p imagesignal. For this reason, there is slight degradation in the imagequality in the 24p image signal after the conversion due to theseprocesses. In contrast, the 60i image signal that has been convertedthrough the 2:3:3:2 pull-down conversion system and the 2:2:2:4pull-down conversion system is not subjected to expanding/compressingprocesses, when inversely converted to a 24p image signal. For thisreason, there is no degradation in the image quality in the 24p imagesignal even after the conversion.

As described above, the 60i image signal is inversely converted to a 24pimage signal. After the conversion, the 24p image signal may beexternally output, or may be recorded on a recording medium (not shown)in the recording device 68. Moreover, the 24p image signal after theconversion may be subjected to an editing process in the editing device67. After the editing process, the resulting 24p image signal may beexternally output, or may be recorded on a recording medium (not shown)in the recording device 68. Here, the expanding device 69 and the imageoutput device 70 are placed so as to allow the editor to recognize theimage state during the editing process carried out by the editing device67.

In the above-mentioned image inverse conversion device, the conversionsystem of the image signal is confirmed by reading conversion systeminformation recorded on the image signal to be input. However, theconversion system of the input image signal can be confirmed based upona repeated pattern of effective flag information (information indicatinga field-data area that is made effective in the 60i image signal afterthe conversion) added to the image signal. Moreover, the conversionsystem can also be confirmed based upon recognition of a repeatedpattern in the image field data.

INDUSTRIAL APPLICABILITY

As described above, in accordance with the present invention, by using arecording device and a display device of an interlace system of 60fields/second, such as the NTSC system, that have been widely used, animage of 24 frames/second can be recorded or displayed.

Further, upon again editing the image, 24 frames at the time of theimage-pickup process can be extracted and edited on a frame basiswithout any degradation in the image quality.

Moreover, upon again editing the image, a joining image-pickup processand a time-code editing process can be carried out by utilizing atime-code through an inexpensive structure.

Furthermore, it becomes possible to select an optimal image-conversionsystem depending on image-pickup purposes and editing methods.

1. An imaging system comprising: an imaging device which picks up an image signal in an image format of 24 frames/second; a temporary recording device which temporarily records the image signal picked up by the imaging device; and a 2:3:3:2 pull-down control device which reads the image signal from the temporary recording device in an interlace format of 60 fields/second, wherein the 2:3:3:2 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth and eighth field data; reading odd field data of the fourth frame as the ninth field data; and
 2. An image conversion system comprising: an input device to which an image signal having an image format of 24 frames/second is input; a temporary recording device which temporarily records the image signal to be input to the input device; and a 2:3:3:2 pull-down control device which reads the image signal from the temporary recording device in an interlace format of 60 fields/second, wherein upon reading first to fourth consecutive frame data of the image signal from the temporary recording device as first to tenth consecutive field data, the 2:3:3:2 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth and eighth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the tenth field data.
 3. The imaging system according to claim 1, further comprising a recording device which records the image signal converted by the 2:3:3:2 pull-down control device in an interlace system of 60 fields/second.
 4. The imaging system according to claim 3, further comprising a compressing device which, with respect to the first to tenth field data read from the temporary recording device, combines paired field data with each other into a piece of frame data, and then compresses the resulting data, wherein the recording device records the image signal that has been compressed by the compressing device.
 5. (canceled)
 6. An image-editing device comprising: an input device to which a compressed image signal in an interlace system having a format of 60 fields/second, which has been combined and compressed on a frame basis, is input; a frame-data extracting control device which selectively extracts from the input device the first, second, fourth and fifth frame data among the first to fifth frame data that form the compressed image signal and are consecutively arranged with each other; a recording/reproducing device which records/reproduces the compressed image signal extracted by the frame-data extracting control device; an image expanding device which expands the compressed image signal reproduced by the recording/reproducing device; an image output device which displays the expanded image signal; and an editing device which edits the compressed image signal reproduced from the recording/reproducing device on a frame basis.
 7. An imaging system comprising: an imaging device which picks up a first image signal in an image format of 24 frames/second; a temporary recording device which temporarily records the first image signal picked up by the imaging device; and a 2:3:3:2 pull-down control device which reads the first image signal from the temporary recording device as a second image signal having an image format of 30 frames/second, wherein the 2:3:3:2 pull-down control device carries out the controlling steps of: converting field data located at odd fields of a frame corresponding a time-code value 4n of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+1 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+1 of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n+1 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+1 of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+1 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+2 of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n+2 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+2 of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+2 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+3 of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n+2 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+3 of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+3 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+4 of the second image signal; and converting field data located at even fields of a frame corresponding a time-code value 4n+3 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+4 of the second image signal (where n is an integer of 0 to 5).
 8. The imaging system according to claim 7, further comprising: a recording device that records the second image signal on a recording medium, wherein the recording device records the second image signal on the recording medium by a unit of 5 frames that corresponds to 1 sequence of the second image signal.
 9. The imaging system according to claim 8, further comprising: a recording start signal generator that generates a recording start signal that is set to a unit of 5 frames that corresponds to 1 sequence of the second image signal.
 10. The imaging system according to claim 8, further comprising: a time-code reading device that reads the time code of the second image signal recorded on the recording medium, wherein the recording device starts a recording process of the second image signal in phase-synchronism with the time code read by the time-code reading device.
 11. The imaging system according to claim 8, wherein the recording device records the second image signal based upon an interlace system of 60 fields/second.
 12. The imaging system according to claim 11, further comprising a compressing device which, with respect to the field data read from the temporary recording device, combines paired field data with each other into a piece of frame data, and then compresses the resulting data, wherein the recording device records the image signal that has been compressed by the compressing device.
 13. An image conversion system comprising: an input device to which a first image signal having an image format of 24 frames/second is input; a temporary recording device which temporarily records the first image signal to be input to the input device; and a 2:3:3:2 pull-down control device which reads a second image signal from the temporary recording device in an image format of 30 frames/second, wherein the 2:3:3:2 pull-down control device carries out the controlling steps of: converting field data located at odd fields of a frame corresponding a time-code value 4n of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+1 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+1 of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n+1 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+1 of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+1 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+2 of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n+2 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+2 of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+2 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+3 of the second image signal; converting field data located at even fields of a frame corresponding a time-code value 4n+2 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+3 of the second image signal; converting field data located at odd fields of a frame corresponding a time-code value 4n+3 of the first image signal to field data located at odd fields of a frame corresponding a time-code value 5n+4 of the second image signal; and converting field data located at even fields of a frame corresponding a time-code value 4n+3 of the first image signal to field data located at even fields of a frame corresponding a time-code value 5n+4 of the second image signal (where n is an integer of 0 to 5).
 14. (canceled)
 15. An image-editing device comprising: an input device to which a compressed image signal in an interlace system having a format of 60 fields/second, which has been combined and compressed on a frame basis, is input; a frame-data extracting control device which extracts pieces of frame data located at frame positions corresponding to time-code values of 5n, 5n+1, 5n+3, 5n+4 (n: an integer of 0 to 5) from the input device; a recording/reproducing device which records/reproduces the compressed image signal extracted by the frame-data extracting control device; an image expanding device which expands the compressed image signal reproduced by the recording/reproducing device; an image output device which displays the expanded image signal; and an editing device which edits the compressed image signal reproduced from the recording/reproducing device on a frame basis.
 16. An imaging system comprising: an imaging device which picks up an image signal in an image format of 24 frames/second; a temporary recording device which temporarily records the image signal picked up by the imaging device; a reading device which reads the image signal from the temporary recording device based upon an interlace system of 60 fields/second; a pull-down control device which is provided with a plurality of corresponding relationships between each frame of the image signal having the image format of 24 frames/second and each field of the interlace image signal having the image format of 60 fields/second, and based upon one corresponding relationship selected from the corresponding relationships, controls the reading operation of the reading device; and a switching device which switches the corresponding relationships to be selected by the pull-down control device.
 17. An imaging system comprising: an input device to which an image signal having an image format of 24 frames/second is input; a temporary recording device which temporarily records the image signal to be input to the input device; a reading device which reads the image signal from the temporary recording device based upon an interlace system having an image format of 60 fields/second; a pull-down control device which is provided with a plurality of corresponding relationships between each frame of the image signal having the image format of 24 frames/second and each field of the interlace image signal having the image format of 60 fields/second, and based upon one corresponding relationship selected from the corresponding relationships, controls the reading operation of the reading device; and a switching device which switches the corresponding relationships to be selected by the pull-down control device.
 18. An imaging system comprising: an imaging device which picks up an image signal in an image format of 24 frames/second; a temporary recording device which temporarily records the image signal picked up by the imaging device; a reading device which reads the image signal from the temporary recording device based upon an interlace system of 60 fields/second; a 2:3:3:2 pull-down control device which controls the reading device; a 2:3:2:3 pull-down control device which controls the reading device; and a switching device which switches control operations of the reading device between the 2:3:3:2 pull-down control device and the 2:3:2:3 pull-down control device, wherein, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:3:2 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth and eighth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the tenth field data, while, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:2:3 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the eighth and tenth field data.
 19. An image conversion system comprising: an input device to which an image signal having an image format of 24 frames/second is input; a temporary recording device which temporarily records the image signal to be input to the input device; a reading device which reads the image signal from the temporary recording device based upon an interlace system having an image format of 60 fields/second; a 2:3:3:2 pull-down control device which controls the reading device; a 2:3:2:3 pull-down control device which controls the reading device; and a switching device which switches control operations of the reading device between the 2:3:3:2 pull-down control device and the 2:3:2:3 pull-down control device, wherein, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:3:2 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth and eighth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the tenth field data, while, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:2:3 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the eighth and tenth field data.
 20. An imaging system comprising: an imaging device which picks up an image signal in an image format of 24 frames/second; a temporary recording device which temporarily records the image signal picked up by the imaging device; a reading device which reads the image signal from the temporary recording device based upon an interlace system of 60 fields/second; a 2:3:3:2 pull-down control device which controls the reading device; a 2:3:2:3 pull-down control device which controls the reading device; a 2:2:2:4 pull-down control device which controls the reading device; and a switching device which switches control operations of the reading device among the 2:3:3:2 pull-down control device, the 2:3:2:3 pull-down control device and the 2:2:2:4 pull-down control device, wherein, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:3:2 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth and eighth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the tenth field data, while, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:2:3 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the eighth and tenth field data, while, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:2:2:4 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the fifth field data; reading even field data of the third frame as the sixth field data; reading odd field data of the fourth frame as the seventh and ninth field data; and reading even field data of the fourth frame as the eighth and tenth field data.
 21. An imaging system comprising: an input device to which an image signal having an image format of 24 frames/second is input; a temporary recording device which temporarily records the image signal to be input to the input device; a reading device which reads the image signal from the temporary recording device based upon an interlace system having an image format of 60 fields/second; a 2:3:3:2 pull-down control device which controls the reading device; a 2:3:2:3 pull-down control device which controls the reading device; a 2:2:2:4 pull-down control device which controls the reading device; and a switching device which switches control operations of the reading device among the 2:3:3:2 pull-down control device, the 2:3:2:3 pull-down control device and the 2:2:2:4 pull-down control device, wherein, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:3:2 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth and eighth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the tenth field data, while, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:3:2:3 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third and fifth field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the seventh field data; reading even field data of the third frame as the sixth field data; reading odd field data of the fourth frame as the ninth field data; and reading even field data of the fourth frame as the eighth and tenth field data, while, upon allowing the reading device to read first to fourth consecutive frame data of the image signal as first to tenth consecutive field data, the 2:2:2:4 pull-down control device carries out the controlling steps of: reading odd field data of the first frame as the first field data; reading even field data of the first frame as the second field data; reading odd field data of the second frame as the third field data; reading even field data of the second frame as the fourth field data; reading odd field data of the third frame as the fifth field data; reading even field data of the third frame as the sixth field data; reading odd field data of the fourth frame as the seventh and ninth field data; and reading even field data of the fourth frame as the eighth and tenth field data. 